IF-NMEA2K2 source selection

A

Anonymous

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I understand from a previous post that the IF-NMEA2K2 cannot be told which N2K data source to use when translating data to 0183.

But how does it decide which source to use? Does it go through a deterministic process to select the source, or is it random? So, by way of example, if I have two heading sensors on N2K, how does the IF-NMEA2K2 decide which to use when feeding data to the 0183 side?
 
The 2k2 will only translate one source of each type of data. So if you have two GPS units, it will translate the first one it finds. If they are the same GPS model, this is normally the GPS sensor with the lowest NMEA 2000 instance number.

Ideally, if you have two items of something like GPS (or heading), on the same network for redundancy, they should be reading basically the same. This way it works, no matter which source the IF-NMEA2k2 translates.

Under true redundancy, it is best to take a completely different data path. For example, the NN3D you could have one source of GPS via 0183 and the other via 2000. To have two 2000 sources using the same data path isn't ideal. If that bus gets broken; you lose both sources. The TZT can have one GPS via the radar (comes down by network) and another via 2000, providing a completely different redundant path. Heading redundancy is nice but not as essential as something like GPS.

Have a good weekend.
 
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